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Surrounding Alveolar Bone (surrounding + alveolar_bone)
Selected AbstractsLife history of a mule (c. 160 AD) from the Roman fort Biriciana/Weißenburg (Upper Bavaria) as revealed by serial stable isotope analysis of dental tissuesINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2010T. E. Berger Abstract The presence of the osseous remains of at least four mules in a garbage dump at the Roman fort of Biriciana near the town of Weißenburg, Upper Bavaria, dating to c. 160 AD, raised the question as to whether mule breeding was already performed to the north of the Alps during the Middle Roman Empire, or whether these animals still had to be imported from the Mediterranean. Serial analyses of the dental enamel and dentine of a lower fourth premolar and the surrounding alveolar bone of a mandible of a mule in terms of stable strontium isotopic ratios of the apatite, and stable carbon and oxygen isotope ratios of the structural carbonate, were carried out to test whether this individual moved long distances during its lifetime. Since isotopic ratios obtained by serial analysis can be correlated with consecutive ontogenetic stages, it can be assumed that this particular individual experienced significant changes in terms of diet and environmental parameters after its eighth year of life. These changes included a period of residence in a region of high altitude, most likely the Alps considering the location of the Roman fort where the mule was found. The isotopic data obtained do not contradict the assumption that this animal was bred and raised in northern Italy, to frequent later in its adult life the Alps and finally perish at Biriciana/Weißenburg. Copyright © 2008 John Wiley & Sons, Ltd. [source] Classification and sequelae of arrested eruption of primary molarsINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 1 2008INGER KJÆR Aim., The aim of this study was to classify early arrested eruption of primary molars and to analyse and explain the sequelae for the surrounding alveolar bone and the succeeding premolar. Design., The position of the arrested primary molars in the mandible, the height of the local alveolar bone, and the morphology and location of the succeeding premolar were evaluated on radiographs from 29 children. Results., Four groups of arrest from mild to severe with regards to infra-position were categorized (Groups I,IV). Mean ages at the time of referral decreased from Groups I (8 years, 10 months) to Group IV (5 years, 9 months). Sequelae., (i) Reduction of alveolar bone height (Groups I,III); (ii) delayed maturity of the succeeding premolar (two-thirds of the cases); (iii) malformation of the succeeding premolar (mainly Groups III and IV); and (iv) ectopically located premolar occlusal to the retained molar (Group IV). Conclusions., The deeper in the alveolar process a primary molar is retained, the earlier the disturbance in the eruption has occurred, and the greater is the risk of the permanent tooth germ being malformed and malpositioned. It is estimated that the earliest occurrences of arrested eruption of primary molars supposedly occur before the age of 3. [source] Phenotypic comparison of periodontal ligament cells in vivo and in vitroJOURNAL OF PERIODONTAL RESEARCH, Issue 2 2001P. Lekic The mammalian periodontal ligament contains heterogeneous populations of connective tissue cells, the precise function of which is poorly understood. Despite close proximity to bone and the application of high amplitude physical forces, cells in the periodontal ligament (PL) are capable of expressing regulatory factors that maintain PL width during adult life. The study of PL homeostasis and PL cell differentiation requires culture and phenotypic methods for precise characterization of PL cell populations, in particular those cells with an inherently osteogenic program. Currently it is unknown if cells cultured from the PL are phenotypically similar to the parental cells that are present in the tissues. We have compared the phenotype of cells in vivo with cells derived from the PL and expanded in vitro to assess the general validity of in vitro models for the study of phenotypic regulation in vivo. Rat PL cells were isolated by either scraping the root of the extracted first mandibular molars (Group A), or by scraping the alveolar socket following extraction of first mandibular molars (Group B), or by obtaining a mixture of cells after disaggregating a block of tissue consisting of first mandibular molar, PL and the surrounding alveolar bone (Group C). Cultured cells at confluence were fixed and immunostained for ,-smooth muscle actin (,-SMA), osteopontin (OPN), alkaline phosphatase (AP), or bone sialoprotein (BSP). For in vivo assessments, frontal sections of rat first mandibular molar were immunostained for ,-SMA, OPN, AP and BSP. We examined osteogenic differentiation of cultured PL cell cultures by bone nodule-forming assays. In vivo and at all examined sites, >68% of PL cells were immunostained for AP; ,50% and ,51% for OPN and ,-SMA (p=0.3), respectively, while only ,8% were positively stained for BSP (p<0.01). Analysis of cultured PL cells in Groups A, B and C showed 54%, 53% and 56% positive staining for ,-SMA respectively; 51%, 56%, 54% for OPN; 66%, 70%, 69% for AP and 2.2%, 1.4% and 2.8% for BSP. The mean percentage of PL cells in situ stained for the different markers was similar to that of cultured PL cells (Group A,Group B,Group C in situ for p>0.2) except for BSP which was 3 to 4 fold higher in vivo(p<0.01). PL cell cultures treated with dexamethasone showed mineralized tissue formation for all groups (A, B, C), but no mineralized tissue formation was detected in the absence of dexamethasone. As PL cells express quantitatively similar phenotypes in vitro and in vivo, we conclude that the in vitro models used here for assessment of PL cell differentiation appear to be appropriate and are independent of the cell sampling method. Further, dexamethasone-dependent progenitors are present both on the root and bone-related sides of the PL. [source] An overview of the dental pulp: its functions and responses to injuryAUSTRALIAN DENTAL JOURNAL, Issue 2007C. Yu Abstract The dental pulp is a unique tissue and its importance in the long-term prognosis of the tooth is often ignored by clinicians. It is unique in that it resides in a rigid chamber which provides strong mechanical support and protection from the microbial rich oral environment. If this rigid shell loses its structural integrity, the pulp is under the threat of the adverse stimuli from the mouth, such as caries, cracks, fractures and open restoration margins, all of which provide pathways for micro-organisms and their toxins to enter the pulp. The pulp initially responds to irritation by becoming inflamed and, if left untreated, this will progress to pulp necrosis and infection. The inflammation will also spread to the surrounding alveolar bone and cause periapical pathosis. The magnitude of pulp-related problems should not be underestimated since their most serious consequence is oral sepsis, which can be life threatening, and hence correct diagnosis and management are essential. Clinicians must have a thorough understanding of the physiological and pathological features of the dental pulp as well as the biological consequences of treatment interventions. [source] | ||||||||||